Method of marking paved surfaces and curable two-part epoxy systems therefor

ABSTRACT

The disclosed coating system comprises a curable liquid epoxide and an amine hardener or co-curative. The amine co-curative comprises a blend of an aliphatic amine (e.g. trimethyl hexamethylene diamine) and a bismethylamino aromatic compound (e.g. a xylylene diamine). This coating system, when suitably combined with a reflectorizing material, has the ability to satisfy some or all of the very troublesome requirements of a highway marking or striping composition and is therefore useful in methods for marking or striping paved surfaces.

FIELD OF THE INVENTION

This invention relates to the application of a road-marking orpavement-marking material to a paved surface for in situ cure. An aspectof this invention relates to a highway marking or striping material towhich the conventional reflective materials can be added, e.g. the typeof glass beads used in the formulation of reflectorized paint. Stillanother aspect of this invention relates to a 100% solids, two-partepoxy coating composition in which part A comprises a curable liquidepoxide and part B comprises a liquid polyfunctional amine hardener(sometimes referred to as an amine co-reactant or co-curative). Stillanother aspect of this invention relates to a unique polyfunctionalamine hardener composition for the two-part coating composition.

DESCRIPTION OF THE PRIOR ART

The use of epoxy resins in reflective markers, curable road-markingmaterials, traffic paint compositions, highway marking compositions orpaints, and the like is very attractive for a variety of technicalreasons, including durability and wear resistance. Many other types ofmarking compositions or highway paints have been both thoroughlyinvestigated and widely used but can be extremely limited in their scopeof application and effectiveness. For example, modified chlorinatedrubber-type coatings are difficult to apply to damp roadway surfaces,and may also be difficult to apply when ambient temperatures are below10° C. Furthermore, once the chlorinated rubber coating is in place,re-coating may be required as soon as three or four months afterapplication.

Several approaches have been suggested for utilizing epoxy resintechnology in the field of highway paints and highway markingcompositions. These various approaches have been designed to solve oneor more of the extremely taxing problems which confront the epoxychemist in this particular field. Indeed, the epoxy chemist is obligedto manipulate several (or even most) of the variables inherent in theknown and theoretically possible 1- and 2-part epoxy coating systems inorder to deal with the complex set of problems imposed by the trafficmarking art. The following list sets forth some of the requirements of astreet or highway marking composition:

Adhesion to siliceous or asphaltic road surfaces.

Resistance to chemical attack by water and/or de-icing salts.

Abrasion resistance with respect to rubber-tired vehicles, sanding,snowplowing, etc.

Minimal solvent hazards during application of the coating, if possible.

Ability to adhere to or hold or retain a glass bead filler or glass beadovercoating, which filler or overcoating provides the requiredreflectorization.

Long-term weather resistance.

Ability to be applied under a wide variety of ambient temperature androad surface conditions, and the ability to become tack-free within ashort time under any of these conditions.

Flowability or sprayability, e.g. adaptability for use with airlessspray equipment.

Good wetting action with respect to the roadway surface.

Flexibility (i.e. ability to move as road surfaces expand, contract,etc.).

If possible, the ability to be applied without previous priming of theroadway surface.

Without careful selection of raw materials and extensive manipulation ofthe variables discussed previously, epoxy resin technology is notnecessarily ideal for meeting all these requirements. For example, someepoxy coating systems are very slow to cure, particularly attemperatures below 20° C. Other epoxy systems may actually cure too fastin the summertime when the roadway surface has been heated up wellbeyond the ambient temperature. (For example, road surface temperaturesin excess of 50° C. and approaching 65° C. can occur in hot summerweather, due to the heat-absorptive characteristics of dark-coloredasphaltic pavements.) Some epoxy coating systems require primers;others, due to the high viscosity of the epoxy prepolymer, require theuse of volatile solvents. Still other epoxy systems can be too rigidafter cure, insufficiently resistant to abrasion, or the like.

Although a number of approaches have been suggested in the traffic paintor highway marking or coating art for dealing with the inherentshortcomings of epoxy coating compositions, e.g. in U.S. Pat. Nos.3,011,412, 2,897,733, 2,952,192, 3,046,851, 3,408,219, 3,418,896,3,446,762, 3,682,054, 3,787,349, and 3,850,661, the prior art approachbelieved to have the most advantages is disclosed in U.S. Pat. No.4,088,633 (Gurney), issued May 9, 1978. Gurney contemplates using acombination of aliphatic and cycloaliphatic amines as the hardener (i.e.the co-curative or co-reactant for the liquid vicinal epoxidecomposition). This amine hardener system appears to be technicallyoutstanding, but the amine raw materials--particularly cycloaliphaticdiamines--can be difficult and expensive to obtain in commerciallyuseful quantities. The type of cycloaliphatic diamines most preferred byGurney are bismethylaminocycloalkanes of the formula

    H.sub.2 N--CH.sub.2 A--CH.sub.2 NH.sub.2

wherein a represents a divalent cycloalkane group such as a cyclohexanenucleus.

A commonly used route for the synthesis of thebismethylaminocyclohexanes involves hydrogenation of their aromaticprecursors, e.g. the xylylene diamines (i.e. bismethylaminobenzenecompounds). Hydrogenation of aromatic rings is, of course, relativelydifficult when compared to the hydrogenation of simple mono- orpolyolefins, even when compared to the conjugated polyolefins. Anexpensive catalyst and high pressures are required. (The hydrogenationof an aromatic ring can be many times as energy-consuming as that ofnon-aromatic unsaturated compounds.) With energy costs continuallyrising and stocks of petroleum-derived chemicals constantly in demand(and sometimes in short supply), it is desirable that an alternative forthe bismethylaminocyclohexanes be found.

The epoxy resin art is, of course, much broader than this particularfield of coating compositions, and it would be difficult to provide evena representative sampling of the whole field of epoxy technology,particularly in view of the enormous utility of these materials (e.g. asadhesives, castings, potting compounds, etc.). Needless to say, a widevariety of amine hardening agents has been used with an equally widevariety of curable epoxide monomers, prepolymers, etc.

SUMMARY OF THE INVENTION

it has now been discovered that the aromatic precursors for thebismethylaminocyclohexanes can be substituted for these cycloaliphaticdiamines with no apparent adverse effect upon the properties of eitherthe uncured or the cured two-part epoxy system of the type contemplatedin the aforementioned Gurney patent. This result is difficult toexplain, since only a methylene bridge separates the primary aminegroups of the xylylene diamine or bismethylaminobenzene precursors fromthe aromatic ring, and with only this small degree of "insulation"between the ring and the amine groups, these precursors would beexpected to have some aromatic amine character (perhaps including atendency toward yellowing under ultraviolet light), some aliphatic aminecharacter, and no cycloaliphatic amine character whatever. It might evenbe expected that xylylene diamines would be approximately intermediatein character between aliphatic diamines, such as alkyl-substitutedhexamethylene diamines and aromatic diamines, such as tolylene diamineor phenylene diamine. These aromatic diamines are considered lessreactive than either the aliphatic or cycloaliphatic diamines. (Theelectron pairs on the primary amine groups can be subject todelocalization.) Accordingly, it is not presently understood why thepossibly partial aromatic amine character of the xylylene diamines isbeneficial in the context of this invention; it appears that thealiphatic diamine/bismethylaminoaromatic combination is synergistic.

A preferred combination of diamines used in the blended amine hardeneror co-curative system (i.e. in the Part B used to cure theepoxy-containing Part A) comprises:

    H.sub.2 N--R--NH.sub.2, and                                (a)

    H.sub.2 N--CH.sub.2 --Ar--CH.sub.2 --NH.sub.2              (b)

wherein R represents an aliphatic chain, and Ar represents an aromaticnucleus, preferably monocyclic.

Thus, the method of this invention involves:

(a) supplying to the point of application the aforementioned blendedco-curative system;

(b) supplying to the point of application a suitable curable liquidvicinal epoxide composition, the proportioning of the epoxidecomposition and co-curative being controlled so as to provide a ratio of3 epoxide equivalents to active hydrogen-bearing amine equivalentsranging from about 1:1 to about 1.5:1;

(c) applying the co-curative and the liquid epoxide to the paved surface(preferably after intimately mixing the co-curative and the liquidepoxide); and

(d) permitting the resulting mixture to cure in situ on the pavedsurface. It is ordinarly preferable to maintain the liquid epoxide andthe co-curative in a moderately heated state prior to application (e.g.heated to a temperature ranging from about 40° to about 90° C.);however, once the epoxy and the curative have been blended and appliedto the road surface (e.g. with airless spray equipment), rapid cureswill ensue without any further application of heat and despite the lackof any special preparation of the asphaltic or siliceous road surface,even in moderately cold weather. For example, a highway stripe orlane-marking applied according to the teachings of this invention can besubstantially tack-free and ready to accept automobile traffic in lessthan an hour after application under ambient temperature conditionsranging from 0° to 40° C. or more.

Using the typical part A-part B terminology, a part A of this inventiontypically comprises a 100% solids polyglycidyl ether of a polyhydricphenol. The typical part B comprises the aliphatic polyamine and thebismethylaminoaromatic compound, blended in a weight ratio ranging from10:90 to 90:10, a portion of this polyamine combination having beenconverted to an amine-epoxy adduct, the epoxy portion of this adductbeing contributed by a diglycidyl ether of a dihydric phenol. It ispreferred that part B also contain a monohydric phenol and a tertiaryalkanolamine. The preferred polyglycidyl ether for use in part A isderived from methylol-substituted bisphenol A and an epihalohydrin. Anydiluents included in the composition are preferably reactive, so thatthe composition still remains substantially in the 100% solids category.For improved adhesion to road surfaces, silane adhesion promoters can beincluded in the epoxy coating composition, e.g. in part A.

DETAILED DESCRIPTION

The basic theory of epoxide chemistry is reasonably well understood,although an exact theoretical explanation for the variety of reactionswhich occur during curing is not always possible. In theory, the vicinalor 1,2-epoxide ring (also called the oxirane ring) can be opened byinteraction with a compound having an available unbonded pair ofelectrons. Once the ring is opened, the door is open to furtherreactions with active hydrogen bearing substituents. The term "activehydrogen", in this context, refers to hydrogen atoms which are activeaccording to the Zerewitinoff test, J. Amer. Chem. Soc. 49, 3181 (1927).When the electron pair-containing compound is an active hydrogen-bearingamine (i.e. a primary or secondary amine), both the electron pair on thenitrogen and the active hydrogen can participate in the reaction. Thereis no perfect term for describing the function of a primary or secondaryamine in this context, it is variously referred to as a "hardener", a"co-curative", or a "co-reactant" for the epoxide. In any event, the netresult is a joining of the amine molecule and the epoxide-containingmolecule, resulting in an increase in molecular weight and, mosttypically, cross-linking between epoxide-containing molecules to yield athermoset resin.

The curable epoxide is also referred to in various ways. Sometimes it iscalled the epoxy "resin". This may be a somewhat misleading way to referto a monomer or prepolymer capable of being cross-linked or hardened orcured to a tough, resinous solid, particularly since the "resin" may bea low molecular weight liquid. Accordingly, the curable liquid vicinalepoxide is referred to hereinafter as the "monomer", it being understoodthat the "monomer" can be in a very low stage of polymerization, wherebyit can contain a few repeating units.

In the preferred practice of this invention, a part A and a part B aremaintained at a moderately elevated temperature, e.g. 40°-90° C., morepreferably about 60°-65° C., using heated storage zones or heated supplylines or the like. The two heated components can then be pumped andautomatically blended in airless spray equipment prior to application ofthe coating onto a highway surface. Preferred application rates providea thin film or layer or coating on the pavement substrate, which coatinghas a thickness generally ranging from about 1 to 100 mils (0.025-2.5mm), more preferably 10-25 mils. This coating thickness corresponds to aspreading rate of approximately 20-1,000 square feet per gallon, moreprefably 50-200 square feet per gallon. Equipment is commerciallyavailable for proportioning, heat-recirculating and/or mixing of thetwo-component system. The two parts are mixed and/or supplied to thespray head in the proper proportion, using this equipment, and theproportioning can be done automatically. For example, the ratio of partB to part A, by volume, can range from 20 to 200 parts per 100, based onthe volume of part A, more preferably the volume ratio of part B:part Aranges from about 1:1 to 1:3 (1:1 to 3:1 in terms of A:B). It isparticularly desirable that there be a slight excess over stoichiometryin the ratio of free epoxide equivalents to active hydrogen-bearingamine equivalents. For most purposes, a 1-10% excess can be sufficient.

In the event that deposits or the like form in the supplying orcirculating line of the storing, mixing, and spraying equipment, thesedeposits can be cleaned out by solvent flushing or cleaning, e.g.cleaning of the mixing manifolds, hoses, and nozzles. Ordinarily, it ispreferred to avoid the use of essentially volatile organic solvents inparts A and B themselves, however.

Stated another way, the part A and part B are preferably substantially100% solids compositions. The term "solids" in this context is borrowedfrom paint chemistry, wherein "solids" includes any components (be theyliquid or solid) which become a part of the ultimately obtained solidcoating. That is, the term "solids" excludes essentially volatilesolvents or carriers. (By "essentially volatile" is meant a liquid whichhas a boiling point or initial boiling point below 150° C. at normalatmospheric pressure.)

In the preferred method of application, glass reflective beads areapplied to the fresh coating of material on the paved substrate, whilethe coating is still in a relatively early stage of cure. In thismanner, the glass beads tend to concentrate near the surface of thecoating, where they are most needed for retroreflection. Despite theconcentration near the surface, however, the glass beads are firmly heldin place and adhere strongly to the epoxy coating. This occurs becausethe beads are wet out fairly thoroughly on their surfaces and partiallypenetrate into the thin layer of epoxy material.

The preferred method of applying the glass beads is to provide a glassbead dispenser immediately "behind" the airless spray nozzle, i.e. veryslightly downstream from the nozzle. Thus, epoxy coating which has beenapplied to the pavement and has been in place for only a fraction of asecond is then overcoated with the flow of beads. The beads can beapplied to the epoxy coating at any suitable rate, e.g. 0.005-0.1 poundsper square foot, more preferably 0.003-0.06 lb/ft².

As noted previously, the most efficient cures are obtained if the part Aand part B are intimately blended prior to application to the pavedsurface. After parts A and B are blended, the resulting mixture has ashort, but workable pot life. Ordinarily, a pot life in excess of fiveor ten seconds is all that is required for sprayability or flowabilityof the mixture. An excessive pot life can be undesirable, since this mayresult in undue traffic delays and rerouting of traffic while the cureis taking place on the road surface. It is particularly desirable thatthe cure be sufficiently advanced to provide a tack-free coating withinone hour, more preferably within 40 minutes. In actual practice,tack-free times as short as 5-10 minutes can be obtained at 20°-25° C.ambient temperature.

Strong adhesion to the road surface is desired, and a silane adhesionpromoter is included in the composition (e.g. in part A) for thispurpose. It has been found that the omega-amino aliphatic trialkoxysilanes are effective in improving adhesion to both siliceous (e.g.portland cement) surfaces and the typical asphalt surfaces, since mostasphalt surfacing materials contain an aggregate which reacts with theSiOH group.

The following is a description in detail of each of the major parts of acoating system of this invention.

Part A: The Curable Liquid Epoxide

This composition contemplates the use of two different types of part Asystems, although both systems have several things in common. Bothsystems contain a polyglycidyl ether of a polyhydric alcohol and, whenopacity is desired, either type of part A can contain a pigment. Theprimary difference between the two types of part A systems is in thedesired cure rate, and, hereinafter, the preferred part A system will bereferred to as the "fast cure" part A.

The key ingredient of the "fast cure" part A is preferably a diglycidylether of a methylol-substituted bisphenol A. As is known in the art, thetypical diglycidyl ethers can be represented by the formula:

    Ep--CH.sub.2 (O--R--O--CH.sub.2 --CHOH--CH.sub.2).sub.n O--R--O--CH.sub.2 --Ep

wherein R represents a divalent residue of a dihydric alcohol, e.g. adihydric mono or polynuclear phenol; n is a number ranging from 0 to 7;and Ep is an epoxide (oxirane) ring. R can be, for example, the residueof bisphenol A. ("Bisphenol A" is a common or trivial name forbis-(4-hydroxyphenol)-2,2-propane). Since mixtures of molecules whereinthe value for n is different commonly occur in commercially availablematerials, the 0-7 range for n can be considered to include fractionalnumbers. In the preferred embodiments of this invention, n willordinarily be 0 or very close to 0, so that epoxy equivalent weightswill generally range from about 150 to 1,000, more preferably less than300.

In the methylol-substituted diglycidyl ethers of bisphenol A, themethylol groups are substituted directly onto the aromatic rings of thebisphenol A nucleus and are usually present in free or unreacted form inthe epoxide monomer composition. These methylol groups are believed toexert an inductive effect upon the diglycidyl ether, which effectincreases the reactivity of the epoxide rings. A particularly strongincrease in reactivity can be obtained with the 3,3'- (i.e. m,m')dimethylolated bisphenol A, which is a symmetric molecule, both methylolsubstituents being substituted meta to the quaternary carbon substituentof the two benzene rings. Dimethylolated bisphenol A-type diglycidylethers are available from M and T Chemicals, Inc., under the tradedesignation "APOGEN". The "APOGEN" products range from 195 to 225 inepoxide equivalent weight and from 6,000 to 30,000 centipoise (cps) inviscosity, the preferred epoxide equivalent weight range being 205-225and the preferred viscosity range being 6,000-9,000 cps at 50° C.,("APOGEN" 104, trade designation of M and T Chemicals, Inc.). So long aspavement temperatures are below about 50° C., the "fast cure" part Asystem can be used. However, for higher pavement temperatures, it ispreferred to include some "slow cure" part A, the slower curing materialbeing a composition containing a low molecular weight diglycidyl etherof bisphenol A; that is, a conventional bisphenol A-type epoxide monomerwhich does not contain substituents on the benzene rings capable ofincreasing the reactivity of the epoxide rings. In the "slow cure" partA, the preferred diglycidyl ethers of bisphenol A have an n value (seethe foregoing formula) which is also very close to 0, so that theepoxide equivalent weight is in the 150-300 range, e.g. 180-200. Suchepoxide monomers are available from several different suppliers undertrade designations such as "EPON" (trademark), "DER" (trademark), etc.

Both the "fast cure" and "slow cure" part A compositions can containseveral other ingredients which will be described in detailsubsequently.

The following table illustrates the amounts of "slow cure" part A and"fast cure" part A preferred for use under various roadway temperatureconditions.

    ______________________________________                                                       Amount of "Fast                                                Roadway Surface                                                                              Cure" Part A,                                                                              Amount of "Slow                                   Temperature    Volume %     Cure" Part A,                                     ______________________________________                                        35-45° F. (2-7.5° C.)                                                          100%         0%                                                45-120° F. (7.5-49° C.)                                                        80-100%      0-20% (pre-                                                                   ferably > 10%)                                    120-140° F. (49-60° C.)                                                        50-75%       25-50%                                            Over 140° F. (over                                                                    50%          50%                                               60° C.)                                                                ______________________________________                                    

Both the "fast cure" and the "slow cure" part A can contain a reactivediluent for reducing viscosity. The preferred reactive diluents areglycidyl ethers of aliphatic mono-ols or polyols, i.e. aliphaticmonohydric or polyhydric alcohols. Among such aliphatic alcohols are theC₄ -C₁₂ aliphatic chains on which one or more hydroxyls are substituted.It is preferred that the epoxide functionality of the resulting glycidylethers ranges from about 1 to about 4, more preferably 1-3. Given therelatively lower molecular weight of the aliphatic chain, epoxideequivalent weights can be well under 300, e.g. 100 to about 385,preferably less than 240.

The selection of the epoxide functionality will depend upon the desiredoverall average functionality for the part A system and the desiredamount of excess over stoichiometry for epoxide in the combined partA/part B coating system. Thus, for example, a small amount of aliphatictriglycidyl ether can compensate for a slight excess of active hydrogenequivalents in the part B component. A particularly useful type oftriglycidyl ether is based on trimethylol alkanes (e.g. trimethylolethane) and has an epoxide functionality of about 2.9 and an epoxideequivalent weight (EEW) within the range of about 150 to about 170.Commercial versions of these polyglycidyl ethers are available fromCelanese Corporation under the trademark "Epi-Rez", e.g. "Epi-Rez" 5044.This triglycidyl ether is very effective in lowering the overallviscosity of a part A system, due to its relatively low viscosity ascompared to diglycidyl ethers of the bisphenol A type. For example, theviscosity can be within the range of about 150 to less than 1,000 (e.g.about 350) centipoise, determined at 77° F., (25° C.).

The low molecular weight and low equivalent weight preferred aliphaticmonoglycidyl and polyglycidyl ethers are fully compatible with thediglycidyl ethers of bisphenol A and are therefore capable of reducingthe viscosity of the curable liquid epoxide without significantlyaltering phase relationships. Due to the substantially negligible vaporpressure of these aliphatic glycidyl ethers, they can serve as diluentswithout creating solvent hazards. To illustrate, the flash point of"Epi-Rez" 5044 is approximately 320° F. (160° C.)--a relatively safeflash point. At the same time, these low equivalent weight glycidylethers do not alter the "100% solids" characteristics of the system,since they react with the active hydrogen in part B.

The aliphatic triglycidyl ethers with an equivalent weight less than 180are particularly useful in "fast cure"-type part A systems. A part Asystem can comprise 5-50% of the low viscosity glycidyl ether, morepreferably 10-30% by weight. Optimum results are obtained with about20-25% by weight. The amount of methylol-substituted diglycidyl ether ofbisphenol A should be larger than the amount of low viscosity aliphaticglycidyl ether, such that on a part per hundred basis(methylol-substituted diglycidyl ether of bisphenol A equals 100 partsby weight), the amount of the low viscosity aliphatic glycidyl etherwill ordinarily range from about 25 to about 75 parts per hundred (phr),more preferably 30-60 phr. Smaller amounts of the low viscosityaliphatic glycidyl ether can be used when the amount of pigment isminimized, larger amounts are needed when the amount of pigment ismaximized. The nature of the pigment and other fillers can also affectthe high viscosity/low viscosity glycidyl ether ratio, e.g. thixotropicfillers and/or pigments can necessitate larger amounts of the lowviscosity monomer.

As will be apparent from the foregoing discussion, the amount of pigmentused in either a "fast cure" or "slow cure" part A of this system variesdepending upon the nature of the pigment, the desired viscosity, and thelike. Pigments with good opacity, such as titanium dioxide can be usedin modest amounts (e.g. less than 30% by weight of the total part Asystem) with good results, the preferred range being 15-25% by weight,depending upon the amount of coloration which is desired. Other pigmentsknown in the art of pigmented 2-part resin systems including thesilicates (including clays), the carbonates (e.g. the various forms ofcalcium carbonate), the sulfates (e.g. barium sulfate), various forms ofsilica, and various metal oxides (which are often used in small amountsto add color to the white opacifying pigments). Pigment particle sizesare generally -200 or even -325 U.S. mesh.

In the case of the "fast cure" part A system, a simple titanium dioxidepigment component will ordinarily suffice. In a "slow cure" part Asystem, however, it is ordinarily preferred to include a more complexpigment-filler-thickener component, e.g. a mixture of the titaniumdioxide and a fumed or colloidal silica thixotrope. The totalpigment-filler-thickener component will generally fall into about thesame range of concentration as the pigment component of the "fast cure"part A, i.e. less than about 30% by weight but generally more than about15% by weight. Based on the total "slow cure" part A system, smallamounts of fumed silica (sometimes called pyrogenic silica) areeffective, e.g. less than 5% by weight. Stated another way, at leastabout 70% by weight of the total pigment-filler-thickener component willordinarily be the pigment portion.

In the "slow cure" system, the viscosity-lowering glycidyl ether (whichalso helps the wetting characteristics of the system) can be arelatively lower viscosity, relatively lower functionality, relativelyhigher EEW material as compared to the preferred aliphatic triglycidylethers of the "fast cure" part A systems. Aliphatic groups in theseglycidyl ethers can range all the way from C₈ to C₁₈ in carbon content.

There is a class of aliphatic glycidyl ethers with varying chain lengthalkyl groups which can be very low in viscosity, e.g. as low as 5-100centipoise at 25° C.; epoxide functionality of these compounds isrelatively low, so that the EEW will tend to range from 200 to about385, more preferably about 225°-240. Despite the very low viscosity,flash points are reasonably safe (e.g. above 100° C.) and volatility isextremely low. At 100 mm Hg, initial boiling points tend to be above100° C. Oxirane oxygen content in weight percent can range from about 4to more than 7%. As in the case of the "Epi-Rez" glycidyl ethers, theseextremely low viscosity glycidyl ethers are compatible with diglycidylethers of bisphenol A. Due to their lower viscosity, however, they canbe used in smaller proportions, e.g. 10-30 phr, more typically 15-25phr, based upon the weight of the diglycidyl ether of bisphenol A in the"slow cure" part A composition.

A commercially available version of these extremely low viscosityaliphatic glycidyl ethers is the family of epoxides commerciallydesignated P & G epoxides #7, #8, and #45. The preferred P & G epoxideis #7, with an EEW ranging up to about 235 and averaging near 230.

As noted previously regarding the triglycidyl ethers of the "fast cure"part A, the low viscosity aliphatic glycidyl ethers are reactivediluents and do not significantly alter the "100% solids"characteristics of the part A system. Of course, to preserve the epoxidefunctionality of either type of part A system, it is generally preferredto avoid strongly acidic fillers, pigments, and the like, pigments andfillers within the pH range of about 6 to about 10 being preferred.

In the "slow cure" part A system, it is generally preferred to includean additional reactive diluent which can be reactive by virtue of thepresence of active hydrogen rather than epoxide substituents. A compoundparticularly preferred for this purpose is dinonyl phenol, which can bemixed with up to about 20 or 25% monononyl phenol. Dinonyl phenol is amonohydric, di-alkylsubstituted phenol with good solvent properties andrelatively low volatility and relatively high flash point. Its boilingrange tends to be above 300° C. and the flash point (clear open cupmethod) is above 170° C. Again, due to the presence of the phenolicactive hydrogen, this solvent does not significantly alter the "100%solids" characteristics of the coating system. Minor amounts ofmonohydric alkyl-substituted phenol are sufficient for viscositycontrol, e.g. less than 10 or 15% of the part A system. It is preferredthat such monohydric phenolic material be substituted with at least 1higher alkyl substituent, i.e. a straight or branched chain alkyl grouphaving at least 7 carbon atoms.

For good adhesion to both asphaltic and siliceous pavement surfaces, itis preferred to include a silane adhesion promoter in any part Acomposition, be it of the "slow cure" or "fast cure" type. The preferredadhesion promoters contain active hydrogen, e.g. by virtue of thepresence of an active hydrogen-bearing amine substituent, which can beeither primary or secondary. The adhesion promoting functional group ofthe compound is typically a trialkoxy silane capable of hydrolyzing to--Si(OH)₃. To minimize stearic hindrance for the primary or secondaryamino group, it is preferred that this group be in the omega position ofan aliphatic chain, e.g. gamma-propyl, beta-ethyl, etc.

For convenience of use in the part A system, it is preferred to form anamine-epoxide adduct from the adhesion promoter, i.e. the reactionproduct of the omega-aminoalkyl trialkoxy silane and a glycidyl ether,preferably a polyglycidyl ether. Among the suitable adducts of this typeare beta-3,4(epoxycyclohexyl) ethyltrimethoxysilane andgamma-glycidoxypropyltrimethoxysilane. Of these, the latter ispreferred. Both are available from Union Carbide Corporation under thetrade designations "A-186" and "A-187", respectively. Since hydrolysisof these compounds produces a lower alkanol, it is preferred, for thesake of efficiency of adhesion promotion, that this alkanol be methanolor ethanol. Accordingly, trimethoxy and triethoxy silanes arepartiulcarly preferred. In any event, the commercially availableadhesion promoters are sufficiently efficient to permit use in verysmall quantitites, e.g. less than 5% by weight of the total part Asystem, more typically 0.1-2% by weight.

The preferred part A systems are summed up in the following table:

    ______________________________________                                                     "Fast Cure"   "Slow Cure"                                                     Part A Amount Part A Amount                                      Component    in wt-% or phr                                                                              in wt-% or phr                                     ______________________________________                                        Diglycidyl ether                                                                           Optional, pre-                                                                              50-70 wt-%                                         of bisphenol A                                                                             ferably less                                                                  than 25 wt-%                                                     Diglycidyl ether of                                                                        50-70 wt-%    Optional, pre-                                     bisphenol A,               ferably less                                       methylol-substituted       than 35 wt-%                                       Low viscosity, low                                                                         Optional      By weight: 10-50                                   functionality C.sub.6      phr, based on                                      aliphatic glycidyl         diglycidyl                                         ether (reactive            ether = 100                                        diluent)                                                                      Low viscosity, high                                                                        By weight: 25-75                                                                            Optional                                           functionality (>2)                                                                         phr, based on                                                    glycidyl ether                                                                             diglycidyl                                                       (reactive diluent)                                                                         ether = 100                                                      Pigment-filler                                                                             15-30 wt-%,   15-30 wt-%,                                        thixotrope compo-                                                                          fillers       filler optional                                    nent         and thixotropes                                                               optional                                                         Higher alkyl-                                                                              Optional      0.5-10 wt-%                                        substituted mono-                                                             hydric phenol                                                                 Adhesion promoter                                                                          0.1-5 wt-%    0.1-5 wt-%                                         Volatile, non-                                                                             Optional, pre-                                                                              Optional, pre-                                     reactive solvent                                                                           ferably less  ferably less                                                    than 5 wt-%   than 5 wt-%                                        ______________________________________                                    

As will be apparent from the foregoing table, these two part A systemsare compatible and can be pre-mixed in any desired ratio from 100:0 upto about 25:75. Alternatively, part A systems intermediate in propertiesbetween the "fast cure" and the "slow cure" systems can be directlyformulated, using various mixtures of diglycidyl ethers of varying curerates. Volatile, non-reactive solvents should be kept to a minimum, sothat the part A system has a substantially "100% solids" capability,e.g. at least 90% solids.

The Part B System

The following description relates to a part B which can be used witheither the "fast cure" or the "slow cure" part A, or any mixture of partA systems. In its essential features, a part B of this inventioncontains a mixture of aliphatic diamine and xylylene-type diaminecombined with 1 or more reactive diluents (if necessary) and/or tertiaryamine initiators and/or reactive epoxides, which epoxides can combinewit a portion of the active hydrogen-containing content of the part Bsystem, thereby providing an epoxy-amine or epoxy-hydroxide adductwithout eliminating all the active hydrogen in the total part B system.Alternatively, the epoxy-amine or epoxy-hydroxide adduct can be formedor synthesized in advance and simply added to the aliphaticdiamine/bismethylaminoaromatic combination.

The preferred aliphatic polyfunctional amines are diamino-substitutedalkanes, typically branched-chained alkyls, having more than two carbonatoms, e.g. more than six carbon atoms. Among these diamino compoundsare the di-primary amines of trimethyl-substituted hexanes, e.g. 2,2,4-or 2,4,4-trimethylhexamethylene diamine. Availablebismethylaminoaromatic compounds have the formula

    H.sub.2 N--CH.sub.2 --Ar--CH.sub.2 --NH.sub.2

wherein Ar represents an aromatic nucleus, preferably monocyclic, e.g.--C₆ H₄ --.

The various position isomers of the xylylene diamines have beensuggested for use in epoxy curing agents; see U.S. Pat. Nos. 3,787,405,3,751,471, 3,609,121, and 3,468,830, and British Pat. No. 1,258,454,published Dec. 30, 1971. The aromatic nucleus of these xylenederivatives can have an unsubstituted xylene nucleus or can have any ofthe four available positions substituted, provided that suchsubstituents do not introduce excessive stearic hindrance or undesiredinductive, electron-donating, or electron-withdrawing effects. Theparticularly preferred bismethylaminoaromatic curing agent for use incombination with aliphatic curing agent is meta-xylylene diamine (MXDA),which is a generally colorless liquid reported to have a freezing pointof 14.1° C., a viscosity of 6.8 centipoise at 20° C., and a specificgravity (d₄ ²⁰) of 1.050. The molecular weight (136) and the equivalentweight (68) of MXDA are very close the molecular weight (142) andequivalent weight (71) of the corresponding cycloaliphatic compound; asa result, a gram-for-gram substitution of MXDA for that cycloaliphaticcompound introduces no significant error in the stoichiometric balance.

The low viscosity of MXDA is an advantage in the context of thisinvention. Some cycloaliphatic diamines such as isophorone diamine canhave an undesirable viscosity-increasing effect. By comparison, thepreferred diamines disclosed by Gurney (U.S. Pat. No. 4,088,633), e.g.1,3- and 1,4-bis(aminomethyl) cyclohexane do have low viscosities and,when available in sufficient quantities, can be blended with MXDA orother xylylene diamines for use in a part B of this invention. Theeconomic advantages of this invention are not realized, however, unlessthe bismethylaminocyclic component of the diamine blend comprises amajor amount of bismethylaminoaromatic compound or compounds rather thanthe hydrogenated analogs.

Since the aliphatic diamines and the xylylene diamines of this inventionare di-primary amines, they can be considered to contain 4 equivalentweights of active hydrogen per mole of compound, even though all 4equivalents may not have equal reactivity in the context of thisinvention.

In terms of active hydrogen equivalent weights, the ratio of xylylenediamine to cycloaliphatic polyfunctional amine ranges from 25:75 to75:25, more typically from 40:60 to 60:40. Since the gram molecularweights of the typical aliphatic and xylylene diamines are not greatlydifferent, weight/weight ratios will be generally within this samerange. Even in the event that a pre-reacted epoxy-amine adduct is addedto unreacted amines to make up a part B of this invention, it isnevertheless preferred that the part B contain at least about 0.9equivalents of active hydrogen per 100 grams of part B. (A preferredpart A of this invention contains more than 0.35 equivalents of epoxideper 100 g.; accordingly, when two parts by volume or about 2.4 parts byweight of part A are combined with part B, stoichiometric requirementswill be satisfied. More typically, the part A contains more than 0.4equivalents per 100 grams, so that 2 parts by volume will provide morethan 0.9 equivalents of epoxide. In the part A/part B combination, aslight excess of epoxide over active hydrogen is preferred.)

The weight ratio of the diamine mixture should be within the range of10:90 to 90:10, preferably within the weight ratios and equivalentsratios discussed previously. In terms of the total part B composition,each diamine will generally be present in the amount of about 5-75% byweight (including the amount necessary to form the aforementionedamine-epoxy adduct), more preferably 5-50% by weight. The balance of thepart B will generally consist essentially of reactive diluents (e.g.active hydrogen-containing substantially nonvolatile solvent materialssuch as the higher alkyl-substituted phenols or otherhydroxide-containing materials), tertiary amine initiators, and theepoxide used to form the epoxide-amine adduct. This last-mentionedmaterial will ordinarily be a polyglycidyl ether of a polyhydric phenol.

In the event that the amine-epoxide adduct is pre-formed and then addedto the amine mixture, it is preferred that the molar ratio of totalactive hydrogen to amine-epoxide adduct in the resulting part Bcomposition be at least 5:1, more preferably 8 to 12:1. The purpose ofthe amine-epoxide adduct is to reduce the moisture sensitivity of thepart B composition and the part A/part B mixture. This helps to permituse of the part A/part B coating system under moist ambient conditions(including wet pavements).

In the following table, a typical part B composition is described. Itwill be understood that the amounts of epoxide and amine, monohydricphenol, trialkanol amine, etc. are expressed in terms of amounts used toform the amine-epoxy adduct in situ during blending of the total part Bsystem. However, this method of expression should be consideredequivalent to the mixture of unreacted active hydrogen-containingcomponents with a pre-formed amine-epoxy adduct. Given the differingreactivities of the various forms of active hydrogen in the compositiondescribed below, it is difficult to predict exact ratios betweenunreacted amine, alkanol, and phenol active hydrogen and the epoxy-amineor epoxy-hydroxide adduct. So long as the ultimately obtained part Bcomposition contains more than about 0.4 equivalents of free primaryamine, however, the nature of these reactions and the order of additionof ingredients is not absolutely critical to the operability of thisinvention.

    ______________________________________                                                   Equivalent Weights                                                 Amount by  Per 100 Grams                                                      Weight     of Part B      Component                                           ______________________________________                                        5-50%      0.4-0.8*       Trimethyl-substi-                                                             tuted hexamethyl-                                                             ene diamine                                         5-50%      0.4-0.8*       Bis(aminomethyl)                                                              benzene                                             5-50%      0.05-25*       Higher alkyl-sub-                                                             stituted phenol                                     0.5-10%    less than 0.2* Reactive tertiary                                                             amine, preferably                                                             triethanolamine                                     5-30%      less than 0.25 Diglycidyl ether                                                              of bisphenol A,                                                               preferably having                                                             an EEW of 180-200                                   ______________________________________                                         *Active hydrogen equivalents                                             

Optimum amounts by weight of the above-identified ingredients are:22-23%, 20-21%, 29-30%; 5-6%; and about 22%, respectively.

The inclusion of triethanolamine in this composition has some beneficialeffects which are not fully understood. It is assumed that the tertiarynitrogen can have an initiating effect on the epoxide ring-openingreaction, and it is further assumed that the hydroxide on the alkanolportion of the molecule can contribute active hydrogen. In any event,both the alkyl phenol and the triethanolamine do not significantly alterthe 100% solids characteristics of the composition. Like part A, thispart B composition has a controlled viscosity and is sprayable.

Reflectorization Filler

It is preferred for traffic marking purposes (particularly highwaymarking), that compositions of this invention either contain or becombined with a reflective filler such as glass or plastic beads orbubbles. It presently appears that the most effective application of thereflectorizing filler is to treat it as a third part which can be addedto the part A/part B coating system, after the coating system has beenapplied to the paved surface. A less effective manner of including thebeads or bubbles is to mix them directly with the part A/part B mixturebefore application to the substrate. This latter approach isparticularly undesirable if the beads or bubbles are easily fractured ina mixing step or if mixing is otherwise made more complicated.

The preferred reflectorizing additive comprises smooth, round,transparent glass spheres (e.g. beads), substantially free of milkiness,film scratch, pits, and air bubbles. The beads preferably have analkalinity number not greater than 2.0, and it is also preferred thatnot more than 30% of the beads shall be ovate or imperfect.

When tested for gradation according to ASTM D1214 (by use of U.S.Standard sieves) the following sieve analysis is typically obtained:

    ______________________________________                                                      Percent (Numerical or                                                         by Weight or by Volume)                                         ______________________________________                                        -10 +200        Substantially 100%                                            +16             Negligible                                                    -20 +30         5-20%                                                         -30 +50         30-75%                                                        -50 +80         9-32%                                                         -80             0-10%                                                         ______________________________________                                    

The following Example illustrates the principle and practice of thisinvention without limiting its scope.

EXAMPLE

The following formulations illustrate a "fast cure" part A, a "slowcure" part A, and a part B of this invention. The part B can be usedwith either the "slow cure" or the "fast cure" part A. When pavementtemperatures are below 45° F., the "fast cure" part A is generally usedalone. For warmer pavement conditions (pavement temperatures above 45°F.), a portion of the "fast cure" part A can be replaced with "slowcure" material. Under extremely hot pavement conditions, a 50:50 mixtureof "fast cure" and "slow cure" can be used as the part A. Otherwise, the"fast cure" material can comprise the major amount of part A.

For optimum stoichiometry (i.e. a slight excess of epoxide over activehydrogen), the ration of part A to part B is 2:1 by volume.

    ______________________________________                                        "Fast Cure" Part A                                                            Percent by Wt.                                                                             Ingredient                                                       ______________________________________                                        50.81%       "APOGEN" 104 (Trademark)                                         20.46%       "EPI-REZ" 5044 (Trademark)                                       19.85%       "UNITANE" OR-600 (Trademark)                                     6.35%        "DER 331" (Trademark)                                            0.80%        "Silane A187" (Trademark)                                        0.40%        Dinonyl Phenol                                                   100.00%                                                                       ______________________________________                                    

    ______________________________________                                        "Slow Cure" Part A                                                            Percent by Wt.                                                                           Ingredient                                                         ______________________________________                                        59.13%     "DER-331" (Trademark)                                              12.36%     "P & G Epoxide #7" (Trademark)                                     3.72%      Dinonylphenol, flashed (Jefferson)                                            Chemical Co., Inc.) Wt. &                                                     monononylphenol (calculated) 10-20%                                0.83%      "Silane A187" (Trademark)                                          20.60%     "UNITANE" OR-600 (Trademark)                                       3.16%      "Cab-O-Sil" M-5 (Trademark)                                        100.00%                                                                       ______________________________________                                    

The materials identified above by trademark have, according to theirsuppliers, the following chemical compositions.

"APOGEN" 104: m,m'-methylol-substituted diglycidyl ether of bisphenol A(the methylol groups being meta with respect to the quaternary carbon);epoxide equivalent weight (EEW): 205-225; viscosity (cps at 50° C.):6,000-9,000; density at 25° C.: 1.13-1.16.

"EPI-REZ" 5044: aliphatic triglycidyl ether derived fromtrimethylolethane and epihalohydrin; average functionality: 2.9; EEW:150-170; viscosity at 25° C.: 150-350 cps.

"UNITANE" OR-600: alumina-treated rutile titanium dioxide, at least 96%TiO₂ (trademark of American Cyanimid Company).

"Silane A187": gamma-glycidoxypropyltrimethoxysilane (trademark of UnionCarbide Corporation). "DER-331": diglycidyl ether of bisphenol A; EEW:186-192; viscosity: 11,000-14,000 cps.

"P & G Epoxide #7": alkyl glycidyl ether containing predominatly n-octyland n-decyl groups; oxirane oxygen: at least 6.8%, typically 7.0%;density (25° C./25° C.): 0.9; viscosity: 10 cps at 25° C.; EEW: lessthan 235, typically 229; IBP at 100 mm Hg: 140° C.

"Cab-O-Sil" M-5: fumed silica produced through the flame hydrolysis ofSiCl₄ at 1100° C.; nominal particle size: 0.012 micron (trademark ofCabot Corporation).

    ______________________________________                                        Part B                                                                        Percent by Wt.                                                                          Ingredient                                                          ______________________________________                                        22.60%    Trimethyl hexamethylene diamine                                               (Thorson Chemical Company), mixture                                           of 2,2,4- and 2,4,4-isomers, boiling                                          point at 760 mm Hg: 232° C.                                  20.25%    m-xylylenediamine (MXDA)                                            29.57%    Nonyl phenol, Gardner color 1;                                                distillation range (modified ASTM                                             5-95%: 291-300° C.                                           21.93%    "DER-332" (Trademark for diglycidyl                                           ether of bisphenol A; EEW: 172.176;                                           viscosity: 4,000-5,000 cps)                                         5.65%     Triethanolamine, 99% (Union Carbide                                           Corporation)                                                        100.00%                                                                       ______________________________________                                    

The manufacturing procedure for part A involves beginning with thebisphenol A-type diglycidyl ether and adding thereto the aliphaticglycidyl ether ("EPI-REZ" or "Epoxide #7") and the "Silane A187". In thecase of the "fast cure" part A, the pigment can be added after the"EPI-REZ" and the silane can be added last. Maintaining the mixingtemperature within the range of 130°-170° F. helps to insure completemixing. Dispersion-type mixing equipment (e.g. a "COWLES" mixer) can beused for dispersion of pigments, fillers, etc. In the "slow cure"composition, it is preferred to disperse the titanium dioxide in the"DER-331", followed by a second dispersion step for the "Cab-O-Sil" M-5,followed by the addition of the "Epoxide #7", dinonyl phenol, and the"Silane".

In the case of the part B, all active hydrogen-containing componentsexcept for the triethanolamine are blended together first. Exothermicheating to 100°-120° F. occurs spontaneously. The mixture is then cooledto 80° F. prior to the addition of the "DER-332". Another exothermresults as the amine or amine-phenol/epoxide adduct is formed. Themixture is then cooled to 80° F. before addition of the triethanolamine.

A part A/part B mixture can be applied smoothly at a thickness of 15mils, followed by an immediate overlay of glass beads.

In a 250-hour ultraviolet light degradation test (ASTM Test E-42), thecured formula of this Example compared very favorably to a cured samplemade according to the Example of U.S. Pat. No. 4,088,633. This resultwas considered surprising in view of the aromatic character ofm-xylylene-diamine (MXDA). As is known in the art, ultravioletdegradation can be controlled to some degree with u.v.-absorbingadditives, and these additives are useful in this invention, but thesamples tested in the aforementioned 250-hour test contained no suchadditives.

The cured, thin-film MXDA-containing sample of this Example was found tocompare favorably with the corresponding curedbisaminomethylcyclohexane-containing formula in other respects also.Viscosity of the uncured part B at 25° C. (ASTM D-2393-68) was actuallylower, compressive strength (ASTM D-695-69) and percent elongation ofthe cured sample appeared to be higher, and Tabor abrasion loss of thecured sample (ASTM C-501-66) was significantly less. The Shore Dhardness (ASTM-D-2240-75) was the same for both cured samples, and thedensity of the unreacted part B (very close to 1 gram per cc) wasapproximately the same, regardless of the diamine component.

What is claimed is:
 1. A two-part coating system capable of forming ahard coating, said coating system consisting essentially of:(a) in afirst part, a pigmented liquid curable vicinal epoxide compositioncomprising a polyglycidyl ether of a polyhydric phenol, saidpolyglycidyl ether having an average epoxide functionality greater than1 but less than 3 and an epoxide equivalent weight greater than 150 butless than 1,000; said first part further comprising a glycidyl orpolyglycidyl ether of an aliphatic mono-ol or polyol as a viscosityreducing, reactive diluent for said first part; (b) in an activehydrogen-containing, epoxide-reactive second part, a blended co-reactantfor said first part, said blended co-reactant consisting essentially ofan amine-epoxy adduct and the following difunctional amines:

    H.sub.2 N--R--NH.sub.2 and

    H.sub.2 N--CH.sub.2 --Ar--CH.sub.2 --NH.sub.2,

wherein R represents a branched alkylene moiety and Ar represents adivalent aromatic group; said difunctional amines being blended in aweight ratio ranging from 10:90 to about 90:10; said amine-epoxy adductcomprising 5-75% by weight of a reaction product of the componentscomprising a said difunctional amine, a diglycidyl ether of a dihydricphenol, and an alkyl-substituted monohydric phenol;said two-part coatingsystem being substantially free of non-reactive, essentially volatileorganic liquid diluents and containing a silane adhesion promoter.
 2. Asprayable two-part coating system according to claim 1 wherein saidsecond part consists essentially of:(c) 5-50% by weight of ahexamethylene diamine, said hexamethylene chain having at least onemethyl substituent thereon; (d) 5-50% by weight xylylene diamine; (e)0.5-10% by weight triethanolamine; and (f) substantially the balance ofsaid second part being said reaction product.
 3. A sprayable, two-partcoating system according to claim 2 wherein a minor amount of thexylylene diamine has been replaced with a bis(aminomethyl) cyclohexane.4. A sprayable, blended, active-hydrogen-containing co-curative agentfor a curable epoxide, said co-curative agent consisting essentiallyof:(a) 5-50% by weight trimethyl-substituted hexamethylene diamine; (b)5-50% by weight xylylene diamine; (c) 5-50% by weight nonyl phenol; (d)5-30% by weight of a diglycidyl ether of a dihydric phenol; and (e)0.5-10% by weight of triethanolamine; a portion of the activehydrogen-bearing components of said co-curative agent having beenreacted with said component (d) to produce an epoxide-amine adductwithout consuming all of the available active hydrogen in saidco-curative agent; said co-curative agent being substantially free ofnon-reactive, essentially volatile organic liquid diluents.
 5. Aco-curative agent according to claim 4, said agent consistingessentially of:(a) 22-23% 2,2,4-trimethyl hexamethylene diamine; (b)20-21% m-xylylenediamine; (c) 29-30% nonyl phenol; (d) about 22% of thediglycidyl ether of bisphenol A having an epoxide equivalent weightwithin the range of 180-200; and (e) 5-6% by weight of triethanolamine.6. A chemically cured layer comprising the coating system of claim 1,the two parts of which have been mixed together and co-reacted.
 7. Amethod for applying a permanent marking to a paved surface,comprising:(a) supplying to the point of application a blendedco-curative agent consisting essentially of (1) aliphatic polyfunctionalamine having the structural formula H₂ N--R--NH₂, wherein R represents abranched aliphatic chain, and (2) bismethylaminoaromatic polyfunctionalamine having the structural formula H₂ N--CH₂ --Ar--CH₂ --NH₂, whereinAr represents a divalent aromatic group; said aliphatic andbismethylaminoaromatic polyfunctional amines being blended in a weightratio ranging from 10:90 to 90:10; (b) supplying to the point ofapplication a curable liquid vicinal epoxide composition comprising apolyglycidyl ether of a polyhydric alcohol; said supplying of saidcurable liquid epoxide composition being controlled so as to provide aratio of free epoxide equivalents to active hydrogen-bearing amineequivalents ranging from about 1:1 to about 1.5:1; (c) applying the saidblended co-curative agent and the said curable liquid epoxidecomposition to said paved surface, whereby said paved surface isprovided with a coating comprising a mixture comprising said blendedco-curative agent and said curable liquid epoxide composition; and (d)permitting said mixture of said step (c) to cure in situ on said pavedsurface.
 8. A method according to claim 7 wherein said blendedco-curative agent consists essentially of a di-primary amine oftri-methyl-substituted hexane and a xylylene diamine.
 9. A methodaccording to claim 8 wherein said xylylene diamine ismeta-xylylenediamine.
 10. A method according to claim 7 wherein saidcurable liquid epoxide composition comprises the diglycidyl ether of amethylol-substituted bisphenol A.